<?php
// Smart Image Resizer 1.4.1
// Resizes images, intelligently sharpens, crops based on width:height ratios, color fills
// transparent GIFs and PNGs, and caches variations for optimal performance

// Created by: Joe Lencioni (http://shiftingpixel.com)
// Date: August 6, 2008
// Based on: http://veryraw.com/history/2005/03/image-resizing-with-php/

/////////////////////
// LICENSE
/////////////////////

// I love to hear when my work is being used, so if you decide to use this, feel encouraged
// to send me an email. Smart Image Resizer is released under a Creative Commons
// Attribution-Share Alike 3.0 United States license
// (http://creativecommons.org/licenses/by-sa/3.0/us/). All I ask is that you include a link
// back to Shifting Pixel (either this page or shiftingpixel.com), but don�t worry about
// including a big link on each page if you don�t want to�one will do just nicely. Feel
// free to contact me to discuss any specifics (joe@shiftingpixel.com).

/////////////////////
// REQUIREMENTS
/////////////////////

// PHP and GD

/////////////////////
// PARAMETERS
/////////////////////

// Parameters need to be passed in through the URL's query string:
// image		absolute path of local image starting with "/" (e.g. /images/toast.jpg)
// width		maximum width of final image in pixels (e.g. 700)
// height		maximum height of final image in pixels (e.g. 700)
// color		(optional) background hex color for filling transparent PNGs (e.g. 900 or 16a942)
// cropratio	(optional) ratio of width to height to crop final image (e.g. 1:1 or 3:2)
// nocache		(optional) does not read image from the cache
// quality		(optional, 0-100, default: 90) quality of output image

/////////////////////
// EXAMPLES
/////////////////////

// Resizing a JPEG:
// <img src="/image.php/image-name.jpg?width=100&amp;height=100&amp;image=/path/to/image.jpg" alt="Don't forget your alt text" />

// Resizing and cropping a JPEG into a square:
// <img src="/image.php/image-name.jpg?width=100&amp;height=100&amp;cropratio=1:1&amp;image=/path/to/image.jpg" alt="Don't forget your alt text" />

// Matting a PNG with #990000:
// <img src="/image.php/image-name.png?color=900&amp;image=/path/to/image.png" alt="Don't forget your alt text" />

/////////////////////
// CODE STARTS HERE
/////////////////////

if (!isset($_GET['image'])) {
    header('HTTP/1.1 400 Bad Request');
    echo 'Error: no image was specified';
    exit();
}

define('MEMORY_TO_ALLOCATE', '100M');
define('DEFAULT_QUALITY', 90);
define('CURRENT_DIR', dirname(__FILE__));
define('CACHE_DIR_NAME', '/assets/uploads/imagecache/');
define('CACHE_DIR', CURRENT_DIR . CACHE_DIR_NAME);
define('DOCUMENT_ROOT', $_SERVER['DOCUMENT_ROOT']);

// Images must be local files, so for convenience we strip the domain if it's there
$image = preg_replace('/^(s?f|ht)tps?:\/\/[^\/]+/i', '', (string)$_GET['image']);

// For security, directories cannot contain ':', images cannot contain '..' or '<', and
// images must start with '/'
if ($image{0} != '/' || strpos(dirname($image), ':') || preg_match('/(\.\.|<|>)/', $image)) {
    header('HTTP/1.1 400 Bad Request');
    echo 'Error: malformed image path. Image paths must begin with \'/\'';
    exit();
}

// If the image doesn't exist, or we haven't been told what it is, there's nothing
// that we can do
if (!$image) {
    header('HTTP/1.1 400 Bad Request');
    echo 'Error: no image was specified';
    exit();
}

// Strip the possible trailing slash off the document root
$docRoot = preg_replace('/\/$/', '', DOCUMENT_ROOT);

if (!file_exists($docRoot . $image)) {
    header('HTTP/1.1 404 Not Found');
    echo 'Error: image does not exist: ' . $docRoot . $image;
    exit();
}

// Get the size and MIME type of the requested image
$size = GetImageSize($docRoot . $image);
$mime = $size['mime'];

// Make sure that the requested file is actually an image
if (substr($mime, 0, 6) != 'image/') {
    header('HTTP/1.1 400 Bad Request');
    echo 'Error: requested file is not an accepted type: ' . $docRoot . $image;
    exit();
}

$width = $size[0];
$height = $size[1];

$maxWidth = (isset($_GET['width'])) ? (int)$_GET['width'] : 0;
$maxHeight = (isset($_GET['height'])) ? (int)$_GET['height'] : 0;

if (isset($_GET['color']))
    $color = preg_replace('/[^0-9a-fA-F]/', '', (string)$_GET['color']);
else
    $color = FALSE;

// If either a max width or max height are not specified, we default to something
// large so the unspecified dimension isn't a constraint on our resized image.
// If neither are specified but the color is, we aren't going to be resizing at
// all, just coloring.
if (!$maxWidth && $maxHeight) {
    $maxWidth = 99999999999999;
} elseif ($maxWidth && !$maxHeight) {
    $maxHeight = 99999999999999;
} elseif ($color && !$maxWidth && !$maxHeight) {
    $maxWidth = $width;
    $maxHeight = $height;
}

// If we don't have a max width or max height, OR the image is smaller than both
// we do not want to resize it, so we simply output the original image and exit
if ((!$maxWidth && !$maxHeight) || (!$color && $maxWidth >= $width && $maxHeight >= $height)) {
    $data = file_get_contents($docRoot . '/' . $image);

    $lastModifiedString = gmdate('D, d M Y H:i:s', filemtime($docRoot . '/' . $image)) . ' GMT';
    $etag = md5($data);

    doConditionalGet($etag, $lastModifiedString);

    header("Content-type: $mime");
    header('Content-Length: ' . strlen($data));
    echo $data;
    exit();
}

// Ratio cropping
$offsetX = 0;
$offsetY = 0;

if (isset($_GET['cropratio'])) {
    $cropRatio = explode(':', (string)$_GET['cropratio']);
    if (count($cropRatio) == 2) {
        $ratioComputed = $width / $height;
        $cropRatioComputed = (float)$cropRatio[0] / (float)$cropRatio[1];

        if ($ratioComputed < $cropRatioComputed) { // Image is too tall so we will crop the top and bottom
            $origHeight = $height;
            $height = $width / $cropRatioComputed;
            $offsetY = ($origHeight - $height) / 2;
        } else if ($ratioComputed > $cropRatioComputed) { // Image is too wide so we will crop off the left and right sides
            $origWidth = $width;
            $width = $height * $cropRatioComputed;
            $offsetX = ($origWidth - $width) / 2;
        }
    }
}

// Setting up the ratios needed for resizing. We will compare these below to determine how to
// resize the image (based on height or based on width)
$xRatio = $maxWidth / $width;
$yRatio = $maxHeight / $height;

if ($xRatio * $height < $maxHeight) { // Resize the image based on width
    $tnHeight = ceil($xRatio * $height);
    $tnWidth = $maxWidth;
} else // Resize the image based on height
{
    $tnWidth = ceil($yRatio * $width);
    $tnHeight = $maxHeight;
}

// Determine the quality of the output image
$quality = (isset($_GET['quality'])) ? (int)$_GET['quality'] : DEFAULT_QUALITY;

// Before we actually do any crazy resizing of the image, we want to make sure that we
// haven't already done this one at these dimensions. To the cache!
// Note, cache must be world-readable

// We store our cached image filenames as a hash of the dimensions and the original filename
$resizedImageSource = $tnWidth . 'x' . $tnHeight . 'x' . $quality;
if ($color)
    $resizedImageSource .= 'x' . $color;
if (isset($_GET['cropratio']))
    $resizedImageSource .= 'x' . (string)$_GET['cropratio'];
$resizedImageSource .= '-' . $image;

$resizedImage = md5($resizedImageSource);

$resized = CACHE_DIR . $resizedImage;

// Check the modified times of the cached file and the original file.
// If the original file is older than the cached file, then we simply serve up the cached file
if (!isset($_GET['nocache']) && file_exists($resized)) {
    $imageModified = filemtime($docRoot . $image);
    $thumbModified = filemtime($resized);

    if ($imageModified < $thumbModified) {
        $data = file_get_contents($resized);

        $lastModifiedString = gmdate('D, d M Y H:i:s', $thumbModified) . ' GMT';
        $etag = md5($data);

        doConditionalGet($etag, $lastModifiedString);

        header("Content-type: $mime");
        header('Content-Length: ' . strlen($data));
        echo $data;
        exit();
    }
}

// We don't want to run out of memory
ini_set('memory_limit', MEMORY_TO_ALLOCATE);

// Set up a blank canvas for our resized image (destination)
$dst = imagecreatetruecolor($tnWidth, $tnHeight);

// Set up the appropriate image handling functions based on the original image's mime type
switch ($size['mime']) {
    case 'image/gif':
        // We will be converting GIFs to PNGs to avoid transparency issues when resizing GIFs
        // This is maybe not the ideal solution, but IE6 can suck it
        $creationFunction = 'ImageCreateFromGif';
        $outputFunction = 'ImagePng';
        $mime = 'image/png'; // We need to convert GIFs to PNGs
        $doSharpen = FALSE;
        $quality = round(10 - ($quality / 10)); // We are converting the GIF to a PNG and PNG needs a compression level of 0 (no compression) through 9
        break;

    case 'image/x-png':
    case 'image/png':
        $creationFunction = 'ImageCreateFromPng';
        $outputFunction = 'ImagePng';
        $doSharpen = FALSE;
        $quality = round(10 - ($quality / 10)); // PNG needs a compression level of 0 (no compression) through 9
        break;

    default:
        $creationFunction = 'ImageCreateFromJpeg';
        $outputFunction = 'ImageJpeg';
        $doSharpen = TRUE;
        break;
}

// Read in the original image
$src = $creationFunction($docRoot . $image);

if (in_array($size['mime'], array('image/gif', 'image/png'))) {
    if (!$color) {
        // If this is a GIF or a PNG, we need to set up transparency
        imagealphablending($dst, false);
        imagesavealpha($dst, true);
    } else {
        // Fill the background with the specified color for matting purposes
        if ($color[0] == '#')
            $color = substr($color, 1);

        $background = FALSE;

        if (strlen($color) == 6)
            $background = imagecolorallocate($dst, hexdec($color[0] . $color[1]), hexdec($color[2] . $color[3]), hexdec($color[4] . $color[5]));
        else if (strlen($color) == 3)
            $background = imagecolorallocate($dst, hexdec($color[0] . $color[0]), hexdec($color[1] . $color[1]), hexdec($color[2] . $color[2]));
        if ($background)
            imagefill($dst, 0, 0, $background);
    }
}

// Resample the original image into the resized canvas we set up earlier
ImageCopyResampled($dst, $src, 0, 0, $offsetX, $offsetY, $tnWidth, $tnHeight, $width, $height);

if ($doSharpen) {
    // Sharpen the image based on two things:
    //	(1) the difference between the original size and the final size
    //	(2) the final size
    $sharpness = findSharp($width, $tnWidth);

    $sharpenMatrix = array(
        array(-1, -2, -1),
        array(-2, $sharpness + 12, -2),
        array(-1, -2, -1)
    );
    $divisor = $sharpness;
    $offset = 0;
    imageconvolution($dst, $sharpenMatrix, $divisor, $offset);
}

// Make sure the cache exists. If it doesn't, then create it
if (!file_exists(CACHE_DIR))
    mkdir(CACHE_DIR, 0755);

// Make sure we can read and write the cache directory
if (!is_readable(CACHE_DIR)) {
    header('HTTP/1.1 500 Internal Server Error');
    echo 'Error: the cache directory is not readable';
    exit();
} else if (!is_writable(CACHE_DIR)) {
    header('HTTP/1.1 500 Internal Server Error');
    echo 'Error: the cache directory is not writable';
    exit();
}

// Write the resized image to the cache
$outputFunction($dst, $resized, $quality);

// Put the data of the resized image into a variable
ob_start();
$outputFunction($dst, null, $quality);
$data = ob_get_contents();
ob_end_clean();

// Clean up the memory
ImageDestroy($src);
ImageDestroy($dst);

// See if the browser already has the image
$lastModifiedString = gmdate('D, d M Y H:i:s', filemtime($resized)) . ' GMT';
$etag = md5($data);

doConditionalGet($etag, $lastModifiedString);

// Send the image to the browser with some delicious headers
header("Content-type: $mime");
header('Content-Length: ' . strlen($data));
echo $data;

function findSharp($orig, $final) // function from Ryan Rud (http://adryrun.com)
{
    $final = $final * (750.0 / $orig);
    $a = 52;
    $b = -0.27810650887573124;
    $c = .00047337278106508946;

    $result = $a + $b * $final + $c * $final * $final;

    return max(round($result), 0);
} // findSharp()

function doConditionalGet($etag, $lastModified)
{
    header("Last-Modified: $lastModified");
    header("ETag: \"{$etag}\"");

    $if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH']) ?
        stripslashes($_SERVER['HTTP_IF_NONE_MATCH']) :
        false;

    $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ?
        stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE']) :
        false;

    if (!$if_modified_since && !$if_none_match)
        return;

    if ($if_none_match && $if_none_match != $etag && $if_none_match != '"' . $etag . '"')
        return; // etag is there but doesn't match

    if ($if_modified_since && $if_modified_since != $lastModified)
        return; // if-modified-since is there but doesn't match

    // Nothing has changed since their last request - serve a 304 and exit
    header('HTTP/1.1 304 Not Modified');
    exit();
} // doConditionalGet()

// old pond
// a frog jumps
// the sound of water

// �Matsuo Basho
?>